fcntl.h

一个简单的操作系统minix的核心代码

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				include/fcntl.h	 	 
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00900	/* The <fcntl.h> header is needed by the open() and fcntl() system calls,
00901	 * which  have a variety of parameters and flags.  They are described here.  
00902	 * The formats of the calls to each of these are:
00903	 *
00904	 *      open(path, oflag [,mode])       open a file
00905	 *      fcntl(fd, cmd [,arg])           get or set file attributes
00906	 * 
00907	 */
00908	
00909	#ifndef _FCNTL_H
00910	#define _FCNTL_H
00911	
00912	/* These values are used for cmd in fcntl().  POSIX Table 6-1.  */
00913	#define F_DUPFD            0    /* duplicate file descriptor */
00914	#define F_GETFD            1    /* get file descriptor flags */
00915	#define F_SETFD            2    /* set file descriptor flags */
00916	#define F_GETFL            3    /* get file status flags */
00917	#define F_SETFL            4    /* set file status flags */
00918	#define F_GETLK            5    /* get record locking information */
00919	#define F_SETLK            6    /* set record locking information */
00920	#define F_SETLKW           7    /* set record locking info; wait if blocked */
00921	
00922	/* File descriptor flags used for fcntl().  POSIX Table 6-2. */
00923	#define FD_CLOEXEC         1    /* close on exec flag for third arg of fcntl */
00924	
00925	/* L_type values for record locking with fcntl().  POSIX Table 6-3. */
00926	#define F_RDLCK            1    /* shared or read lock */
00927	#define F_WRLCK            2    /* exclusive or write lock */
00928	#define F_UNLCK            3    /* unlock */
00929	
00930	/* Oflag values for open().  POSIX Table 6-4. */
00931	#define O_CREAT        00100    /* creat file if it doesn't exist */
00932	#define O_EXCL         00200    /* exclusive use flag */
00933	#define O_NOCTTY       00400    /* do not assign a controlling terminal */
00934	#define O_TRUNC        01000    /* truncate flag */
00935	
00936	/* File status flags for open() and fcntl().  POSIX Table 6-5. */
00937	#define O_APPEND       02000    /* set append mode */
00938	#define O_NONBLOCK     04000    /* no delay */
00939	
00940	/* File access modes for open() and fcntl().  POSIX Table 6-6. */
00941	#define O_RDONLY           0    /* open(name, O_RDONLY) opens read only */
00942	#define O_WRONLY           1    /* open(name, O_WRONLY) opens write only */
00943	#define O_RDWR             2    /* open(name, O_RDWR) opens read/write */
00944	
00945	/* Mask for use with file access modes.  POSIX Table 6-7. */
00946	#define O_ACCMODE         03    /* mask for file access modes */
00947	
00948	/* Struct used for locking.  POSIX Table 6-8. */
00949	struct flock {
00950	  short l_type;                 /* type: F_RDLCK, F_WRLCK, or F_UNLCK */
00951	  short l_whence;               /* flag for starting offset */
00952	  off_t l_start;                /* relative offset in bytes */
00953	  off_t l_len;                  /* size; if 0, then until EOF */
00954	  pid_t l_pid;                  /* process id of the locks' owner */
00955	};
00956	
00957	
00958	/* Function Prototypes. */
00959	#ifndef _ANSI_H
00960	#include <ansi.h>
00961	#endif
00962	
00963	_PROTOTYPE( int creat, (const char *_path, Mode_t _mode)                );
00964	_PROTOTYPE( int fcntl, (int _filedes, int _cmd, ...)                    );
00965	_PROTOTYPE( int open,  (const char *_path, int _oflag, ...)             );
00966	
00967	#endif /* _FCNTL_H */